Chair and Institute for Engineering Design

Boost Fund - TEPHA eng&nbsp &nbsp

Systematic application of renewable materials for technical products and domains

TEPHA - Technical Product Harvesting

Technical Product Harvesting - Utilizing nature's potential

With the term ‘Technical Product Harvesting’, the project team describes the utilization of suitable biomass for the fabrication of technical products. In particular, the research focuses on organic material that can be shape manipulated during its growth and can then be utilized as a semi-finished product in architectural or mechanical engineering applications.

Besides creating a closed recycling loop, the application of renewable resources for near-net-shape semi-finished products benefits from a natural and ‘automatic’ topology optimization, which, for instance, results from the load-adaptive growth of plants.

The TEPHA project is being funded as a two year ‘Boost Fund’ by the Exploratory Research Space (ERS) of the RWTH Aachen University with means from the Excellence Initiative by the German federal and state governments to promote top-level research at German universities. .

Motivation

The three-dimensional formation of organisms provides design opportunities that can benefit functional, aesthetical as well as semantic aspects of product design. A near-net-shape growth of organic material allows for a reduction of industrial production steps, which in turn minimizes energy- as well as resource consumption, reduces operative time and capital investments in machines. In the context of dwindling resources and an increasing environmental impact of the industrial production of goods, this approach is of great relevance - ecologically as well as economically.

To holistically evaluate the TEPHA approach, insights into the construction method as well as the production of raw materials, the resource consumption and the material recycling at the end of the product lifecycle have to be gained.

Approach and Objectives

In the course of this multidisciplinary project, the suitability of biological and organic material for the natural production of geometrically defined semi-finished products as a substitute for technical material in mechanical engineering and architecture will be analyzed and assessed. As a basis, the technical requirements of sample products for applications in architecture and mechanical engineering made of conventional material, as well as the technical and botanical characteristics of plants are being determined. The objective is to identify suitable renewable equivalents to conventional materials and to assess these equivalents for their usability in industrial production processes. In the process, economic feasibility as well as eco-toxicological aspects are being incorporated into the assessment.

Methodical Approach

A database which links technical requirements with biological characteristics allows for a systematic basis to substitute conventional materials with natural alternatives. The database is based on the functional approach in dependence on the design methodology of Pahl/Beitz and Koller. Here, the before-mentioned product categories are being classified and the products are being reduced to their basic function. This approach should facilitate the identification of natural materials that have adequate material properties to be used for a specific function that has previously been fulfilled by a conventional material. At the same time, this will also allow future engineers to detect unconventional, renewable materials and will give them a comprehensive view on ecological and economic consequences associated with the application of renewable resources.

Experimental Approach

After a comprehensive analysis of typical engineering products, consumer goods and building components it became clear, that material grown into a near-net-shape is best suited for components that perform the functions ‘direct forces’ and ‘absorb forces’. In accord with this insight, exemplary signature organisms have been chosen to grow into pre-defined geometries during the first growth period of the project duration. The organisms are bamboo, calabash and mycelium, which grows on wood-based bio waste. All three organisms have been chosen due to their comparatively fast growth and their expected mechanical stability. Additionally, young alder has been shaped into pre-defined angles prior to the initiation of the growth in girth.

So far, a shape manipulation of all chosen organisms was successful.

Analytical Approach

Mechanical and cellular analyses are being conducted in order to determine the modifications of the organisms caused by the growth manipulations. Tests with a hydraulic testing machine demonstrated the mechanical capacity of the organisms through tensile- and compressive tests. A loss of mechanical strength caused by the growth manipulation is not to be expected. Thermally formed bamboo, on the other hand, demonstrates a significant deterioration of tensile strength in comparison to bamboo that has not been shaped with high temperatures. Microscopic cell analyses confirm the results of the mechanical tests. After the structure and behavior of the organisms is identified, it is possible to simulate the organisms via the finite-element-analysis (FEA).

Ecological Assessment

As part of a ‚Life Cycle Assessment‘ (LCA), the ecological impact of the approach will be assessed using a sample product. Thereby, a conventionally manufactured product will be compared to a product grown into a near-net-shape. The assessment is being carried out via an environmental performance evaluation, which traces the individual steps in the lifetime of a product from the primary production to the waste disposal.

By utilizing domestic plants and recycling the forming tools applied to the plants during the shape manipulation, the environmental performance evaluation can be improved significantly.

User Acceptance

Expert interviews with representatives from politics, research, and industry are being conducted in the near future. This survey allows to assess the potential of before-mentioned products in relation to their societal impact and relevance, design, costs …